Jaén is home to the historic castle of Otar, which dates back to the Middle Ages. It has been identified as a Culturally Significant Object.

On the route between Jaén and Quiebrajano, about 13 kilometres from the capital city, on the Valdearazo River, sits the uninhabited village of Otar, perched atop a hill with convenient access. The castle sits at the peak of the hill, on the narrowest point of the plateau.

The castle's layout is long and narrow, and its brick perimeter uses natural defences to its advantage on the building's eastern side. The remaining wall is stronger, and there is even a mini bastion on the western side. There are ruins of houses and a cistern inside the enclosure.

A tiny fortress was constructed in the southern section of the enclosure, on a rocky outcrop, and it is still there today. Ashlar masonry is used in its construction, and there is a beautiful two-story keep situated on the edge of the cliff. The brick half-barrel vaults in the tower's interior rooms are sturdy and reliable. The stairwell to the upper floors is built into the walls for easy access.

It appears that Otaar was a farming community with few fortifications before the Pact of Jaén. Following the demarcation of the border, this location assumed a significant role in the monitoring of the Sierra Sur de Jaén mountain passes connecting Jaén with the Granada Prebético. Even though the alcazarejo is thought to be from the 15th century and the enclosure may have been built upon other older constructions of Andalusian origin, its construction is typically ascribed to the second half of the 13th century.

Part of Jaén's fortifications, it allowed for visual communication between the city's castle and the Torrebermeja watchtower.